JPS6148330B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for inserting a cable that causes deep damage to a pipe body, and more particularly to a device that prevents backflow of water for feeding the cable and allows the cable to be inserted well into a predetermined pipe body. .

Heat exchangers used in nuclear reactors often have heat exchanger tubes bent into complex shapes to improve heat transfer efficiency, especially multilayer helical coils. In this case, if the heat transfer tube is damaged and the internal fluid comes into contact with the heat transfer medium, a serious accident may occur. In particular, if the fluid in the heat transfer tube is water and the heat transfer medium is sodium, there is a risk that if the two come into contact, they will react explosively and cause a catastrophic accident such as destruction of the heat exchanger. For this reason, it is necessary to periodically perform flaw detection on the heat exchanger tube, but flaw detection from the outside of the heat exchanger tube is not necessarily sufficient, and flaw detection from the inside of the heat exchanger tube is desired. The inventors have developed and put into practical use a flaw detection cable in which a flaw detection device is attached to the tip of the cable and floats are attached at equal intervals for flaw detection from the inner surface of a heat exchanger tube. FIG. 1 shows this cable insertion device for flaw detection.

In the figure, water W is injected and filled into the main body 26 of the apparatus, and a flaw detection cable 25 wound around a drum 22 is sent out by rotating a handle 23. The fed cable 25 enters the heat exchanger tube 27 through the nozzle 28 along the flow of water in the device and into the heat exchanger tube 27 where deep damage is to be performed, and advances with the flow of water.
Flaw detection is performed from the inner surface of the tube using a flaw detection device (not shown) attached to the tip. In the case of this device, if the rotation speed of the handle 23 is too fast, the cable 25 will become slack, and the cable will float up inside the device due to the buoyancy of the float 29, and in severe cases, it will get tangled within the device and become impossible to send out. . In this case, the repair must be carried out by removing the bolts 38, removing the top cover 21, and draining the water inside the device, which is inconvenient to handle. Another problem with this type of device is that, since the state of the cable being extended cannot be observed from the outside, an accident may not be noticed until the device becomes inoperable.

In addition, the length of the tube to be tested for flaws reaches approximately 100 mm in the case of multilayer helical coils, but as the cable is inserted into such a long tube, the resistance inside the tube increases as the cable moves forward, causing water leakage. The flow becomes worse. If the water pressure is increased to advance the cable further, the water will tend to flow backwards and eventually the cable will no longer be able to advance.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus that eliminates the above-mentioned problems, allows confirmation of the cable insertion state, and allows the cable to be inserted efficiently without causing water supply to flow backwards.

In short, this invention forms a seal part for preventing backflow in the cable insertion part of the main body of the device, and this seal part and the float of the cable prevent the backflow of supplied water, and the reduction in the forward force of the cable due to passing through the seal part is prevented. This is supplemented by a cable feeding mechanism placed inside the device body.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 2, an upper plate 30 is placed on the upper part of the cable insertion device main body 1 via a bearing 31, and a main sprocket 5a and a sub sprocket 5b supported via a spring 3 rotate the upper plate 30. Accordingly, the cable 25 is configured to rotate around the descending cable 25. If the cable 25 is twisted as a result, the upper plate 30 is rotated in a predetermined direction to untwist the cable.

Next, as shown in FIG. 3, in the cable passage tube 1a of the apparatus main body 1, a seal 9 made of a flexible material such as rubber is formed on the inner wall of the tube through which the cable 25 passes. This seal 9 has constricted portions 9a formed at approximately equal intervals with respect to the traveling direction of the cable 25, as shown in the figure. The inner diameter of the throttle part 9a is the same as the float 2 attached to the cable 25 at approximately equal intervals.
9, the float 29 and this constriction prevent backflow of water for advancing the cable, which will be described later.

Arrow 6 indicates a cable feeding mechanism, which supplements the forward force of the cable that is attenuated by passing through the cable passage tube 1a. Figures 4A and 4B show details of the cable feed mechanism. A space 40 for installing a feeding mechanism is formed approximately at the center of the apparatus main body 1, and the cable passage 2 is formed and arranged to pass through this space 40 approximately at the center. 8a, 8
b is a rotating ring, each rotating ring is connected with a sprocket 41;
Both rotating rings 8a and 8b connect to chain 1 through
It is linked by 0. Reference numeral 49 denotes a cable feeding plate formed on each rotating ring, and the cable feeding plate 49 engaged with the float 29 advances the cable 25 as the rotating ring rotates. Similarly, the rotating rings 8c and 8d are also linked by another chain 10. 8a and 8c of these rotating rings
The rotating shafts protrude outside the main body of the apparatus, and all rotating rings 8a, 8b, 8c, and 8d rotate in conjunction with each other by engagement of gears 42 and 43 provided on each rotating shaft. 44 is a handle attached to the gear 43, and by rotating this handle, the four rotating rings described above are rotated. Note that it is of course possible to attach a motor in place of the handle 44 and rotate each rotary ring by the motor.

FIG. 5 shows another embodiment of the invention. In this embodiment, the rotating ring is eliminated and the cable feeding plate 49 is directly attached to the chain 10 which is stretched parallel to the moving direction of the cable 25 between the upper and lower sprockets 41a and 41b. As a result, the cable feeding plate 49 moves parallel to the traveling direction of the cable 25, so that the feeding force of the cable 25 can be increased.

Next, the operating state of the above-mentioned device will be explained.

When inserting the flaw detection cable 25 into the pipe body to be flawed, first, water supply W is injected into the cable passage 2 through the water supply nozzle 7 in the direction in which the cable travels, and the cable 25 is advanced by this ejection force.
In this case, the forward force of the cable is reduced by the seal 9 of the cable passage tube 1a, so the rotary ring 8
a, 8b, 8c, and 8d are rotated to compensate for the forward force reduced by the cable feeding plate 49. Note that the seal 9 can almost completely prevent the pressurized water from flowing backward.

By carrying out this invention, the reverse flow of water supply can be almost completely prevented, while the forward force of the cable can also be supplemented, so even if the pipe to be tested is a long pipe, the pipe can be freely tested for flaws.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional tube insertion device, FIG. 2 is a sectional view of a tube insertion device according to the present invention, FIG. 3 is a sectional view of a cable passage tube, and FIG. 4A is a sectional view of the same figure B. An AA sectional view, an enlarged partial view of the main body of the cable insertion device in Figure B, and FIG. 5 are an enlarged partial view of the cable insertion device showing another embodiment. 1... Cable insertion device main body, 2... Cable passage, 6... Cable feeding mechanism, 8a, 8b, 8
c, 8d... Rotating ring, 9... Seal, 9a...
...Aperture section, 10...Chain, 25...Flaw detection cable, 29...Float, 41a, 41b...
Sprocket, 49...Cable feeding plate.

Claims (1)

[Scope of Claims] 1. In a device in which a flaw detection cable having a flaw detection device at the tip of the cable and floats attached to the cable at approximately equal intervals is advanced inside a tube to be flawed by the flow of water supply, Inside the cable passage tube, a seal is formed with a multi-stage constriction part with an inner diameter that is almost the same as the outer diameter of the float, and a cable feeding plate is installed inside the device body to supplement the forward force of the flaw detection cable. A cable insertion device having a cable feeding mechanism. 2. A cable insertion device having a cable feeding mechanism according to claim 1, wherein a rotating ring interlocked with a chain is disposed within the device main body, and the cable feeding plate is attached to the rotating ring. 3. The cable according to claim 1, characterized in that a chain is stretched across a sprocket arranged in the device so as to be parallel to the direction in which the cable travels, and a cable feeding plate is attached to this chain. Cable insertion device with feeding mechanism.